Material Characterization Techniques Research Articles

Comparing Methods for Pyrite Surface Area Measurement Through Optical, Aqueous, and Gaseous Approaches

Accurate surface area data are imperative for the development of meaningful property–function relationships. Nitrogen gas (N2) adsorption/Brunauer–Emmet–Teller (BET) surface area analysis is a widely used technique for surface area characterization of materials because of straightforward sample preparation, automation, and low cost. However, iron disulfide (FeS2) does not typically exhibit quantifiable N2 monolayer formation in BET measurements. FeS2 has been applied in fields such as batteries, catalysis, and adsorption, all of which would benefit from techniques that reliably assess surface area (SSA) of the active material. To address this, we evaluated FeS2 samples by combining alternative surface characterization techniques to quantify SSA. Ten different FeS2 samples from various manufacturers are characterized via BET, laser diffraction, scanning electron microscopy, non-contact profilometry, and liquid dye adsorption. Compared to BET, which resulted in a wide range of SSAs between 0.049–1.213 m2 g−1, liquid dye adsorption was found to be accurate for pyrite samples at low sample masses (<50 mg), with SSA values between 0.99–10.20 m2 g−1. Using an optical characterization approach, which combined particle size and surface roughness data, we readily estimated SSA of the particles and found these values correlated linearly with liquid adsorption but not BET values. This work serves to help researchers choose a more fitting method for examining low surface area materials like FeS2 and can easily be applied to other minerals for quantitative and qualitative surface area comparisons.

Assessing the Integrity of N95 Mask Elastomer Straps With Decontamination and Reuse

ABSTRACTThe rapid progression of the COVID‐19 pandemic revealed an inability to meet increased demand for N95 respirators. These respirators are designed to be used once and disposed, but throughout the pandemic, there was a need for their decontamination and reuse. This research investigates the effect of various decontamination methods on the chemical and mechanical properties of N95 mask straps made of natural rubber to explore how these straps change after decontamination and what materials characterization techniques are well‐suited to evaluate these changes. Using results from ozone decontamination, tensile testing of mask strap assemblies is identified as the most reliable way to quantify changes in strap properties with decontamination and reuse when compared to other analytical techniques. Additionally, visible strap degradation often precedes both strap failure and material property changes and can be a reasonable indicator to discontinue use. Aside from ozone, decontamination with other methods such as heat and UV light appears to be less damaging to the tested materials. Beyond the specific results presented, this study provides insight on testing strategies that can be employed to move forward with evaluating new materials and decontamination methods for use in future pandemics or in more resource‐limited regions.

Dynamic Mechanical Properties and Energy Absorption Capabilities of Polyureas Through Experiments and Molecular Dynamic Simulation.

Polyurea (PUR) has been widely used as a protective coating in recent years. In order to complete the understanding of the relationship between PUR microstructure and its energy absorption capabilities, the mechanical and dynamic performance of PURs containing various macrodiol structural units were compared using material characterization techniques and molecular dynamic simulation. The results showed that the PUR polycarbonate diols formed as energy absorbing materials showed high tensile strength, high toughness, and excellent loss factor distribution based on the comparison of stress-strain tensile curves, glass transition temperatures, phase images, and dynamic storage loss modulus. External energy from simple shear deformation was absorbed to convert non-bond energy, in particular, based on fractional free volume, interaction energy, and total energy and hydrogen bond number change from the molecular dynamic simulation. Hydrogen bonds formed between soft segments and hard segments in the PURs have been proven to play a significant role in determining their mechanical and dynamic performance. The mechanical and dynamic properties of PURs characterized and tested using experimental techniques were quantified effectively using molecular dynamic simulation. This is believed to be an innovative theoretical guidance for the structural design of PURs at the molecular level for the optimization of energy absorption capabilities.

The impact of glidants on the rheological properties of active pharmaceutical ingredients: A study of conventional and alternative flow enhancers.

Nowadays, most of the newly developed active pharmaceutical ingredients (APIs) consist of cohesive particles with a mean particle size of <100μm, a wide particle size distribution (PSD) and a tendency to agglomerate, therefore they are difficult to handle in continuous manufacturing (CM) lines. The current paper focuses on the impact of various glidants on the bulk properties of difficult-to-handle APIs. Three challenging powders were included: two extremely cohesive APIs (acetaminophen micronized (APAPμ) and metoprolol tartrate (MPT)) which previously have shown processing issues during different stages of the continuous direct compression (CDC)-line and a spray dried placebo (SD) powder containing hydroxypropylmethyl cellulose (HPMC), known for its sub-optimal flow with a high specific surface area (SSA) and low density. Four flow-enhancing excipients were used: a hydrophilic (Aerosil® 200) and hydrophobic (Aerosil® R972) fumed silica grade, a mesoporous silica grade (Syloid® 244FP), and a calcium phosphate excipient (TRI-CAFOS® 200-7). The APIs and binary API/glidant blends (varied between 0.5-2.75 w/w%) were characterized for their bulk properties relevant for CDC. The results indicated that optimizing different bulk parameters (e.g., density, flow, compressibility..) of an API required varying weight percentages of the glidant (e.g., different surface area coverage (SAC)) depending on the APIs. Moreover, even at similar SAC, the impact of the glidant on the bulk characteristic of the APIs depended on the glidant type properties. While nano-sized silicon dioxide were effective for improving the flowability of a powder, other glidants (mesoporous silica and tricalcium phosphate (TCP)) showed also promise as alternatives. Additionally, an excess of glidant, referred to as oversilication, negatively impacted some bulk parameters, but other characteristics were unaffected. Finally, to determine the appropriate concentration of the different classes of glidants, SAC calculations, an understanding of the glidant's working mechanism, and knowledge about the API's characteristics (i.e., morphology, compressibility, flowability, aeration, density, and wall friction) are required. This study confirmed the necessity of including various material characterization techniques to assess the impact of glidants on the bulk characteristics of APIs.

Exploring the impact of CO2 sequestration on plastic properties, mechanical performance, and microstructure of concrete

In view of global warming, carbon sequestration techniques are being employed across the globe to minimize the damaging effects of greenhouse gases on the environment. Studies have revealed that adding CO2 during the mixing or curing stage of concrete enhances its mechanical properties and long-term durability. This study aims to examine the effect of CO2 addition during the mixing stage on the plastic, mechanical and microstructural properties of concrete. Various CO2 dosages, ranging from 0.1 to 1%, were injected during mixing to analyze the plastic and hardened properties of concrete. CO2 primarily reacts with calcium hydroxide in concrete to form calcium carbonate (CaCO3), thereby densifying its microstructure and improving its compressive strength by 10–20%. An optimum strength of up to 20% was achieved with 0.75% dosage. Additionally, the results show a 5–10% improvement in flexural and split tensile strength with CO2 addition over the control mix, with 0.75% dosage yielding optimal strength. Semi-adiabatic calorimetry test on early hydrating concrete shows a 14% peak temperature rise at 0.75% CO2 dosage compared to control concrete, indicating enhanced early-age strength development. Thermal Pyrolysis tests, microscopy and infrared spectroscopy indicated the presence of CaCO3, thereby confirming the carbonation process. However, CO2 dosages above 0.5% by weight of cement resulted in a drop in the workability of concrete in the plastic stage. This research attempts to create a simplified CO2 sequestration process in concrete, develop a predictive model to estimate the compressive strength and utilize material characterization techniques to identify the mineralization process.HighlightsInjecting CO2 into fresh concrete improves its strength and lowers its environmental impact.A multiple linear regression model predicts the compressive strength of CO2-injected concrete.Semi-adiabatic calorimetry shows that CO2 injection speeds up early hydration.Thermal Pyrolysis detects mass loss stages linked to dehydration and calcite breakdown.Microscopy and spectroscopy indicate CaCO3 crystal formation in CO2-sequestered concrete.

Evaluation of the effect of biofeedback system driven by optoelectronic conjugate materials in VR exercise rehabilitation

Presently, Exercise Rehabilitation is crucial to restoring and improving a person’s well-being in physical fitness. The present research investigates the significance of Optoelectronic Conjugate Materials (OCM) in Biofeedback Systems to enhance the effectiveness of Virtual Reality (VR) Exercise Rehabilitation. This work presents the Design of Biofeedback System-driven Optoelectronic Conjugate Materials (DBS-OCM), which offers a novel methodology to enhance VR Exercise Rehabilitation. The DBS-OCM framework amalgamates synthesis and material characterization techniques for tissue healing during VR Exercise Rehabilitation. The present research aims to elucidate a resistance trainer’s design and preparation methodology during the Evaluation of the Effect of a Biofeedback System Driven by OCM. This approach seeks to optimize the flexibility of the system to cater to individual requirements during VR Exercise Rehabilitation. The experimental findings demonstrate notable advancements, including a 93.9% augmentation in tissue regeneration, a 95.5% enhancement in the efficacy of resistance training, and a 95.5% boost in involvement during virtual reality exercise. The results highlight the DBS-OCM’s capacity to enhance the Biofeedback System’s efficiency Driven by Optoelectronic Conjugate Materials in VR Exercise Rehabilitation. These findings provide essential insights that have the potential to shape future research endeavors and facilitate the development of practical applications in the domain of VR Exercise Rehabilitation.

Binder-Coated Carbon Cloth Electrodes for All-Vanadium Redox Flow Batteries

Vanadium redox flow batteries (VRFBs) are a promising solution for integrating intermittent renewable energy sources into the existing power grid. However, enhancing the electrochemical performance of VRFBs is critical for their widespread adoption in grid-scale energy storage. This study investigates the impact of adding a porous binder to a carbon-cloth electrode, with a focus on optimizing thermal activation conditions. The electrochemical performance of the binder-coated electrodes compared to uncoated electrodes is evaluated through electrochemical impedance spectroscopy, polarization curve measurements, and charge-discharge cycling. The surface morphology and structural integrity of the binder-coated electrodes at each activation stage are examined using various material characterization techniques to assess the effects of thermal activation. The results are benchmarked against the experiments using non-coated electrodes to determine the performance improvements offered by the binder coating. Notably, the study reveals that binder-coated electrodes exhibit significantly lower resistance and improved efficiency compared to their uncoated counterparts, with optimal activation conditions enhancing performance metrics crucial for VRFB applications. These findings provide valuable insights for further optimizing electrode design and activation strategies, advancing the development of more efficient VRFB systems for large-scale energy storage.

Exploiting the Synergistic Effect of β-Cyclodextrin Functionalized-Multi-Walled Carbon Nanotubes and Zn-MOF for the Detection of Endocrine-Disrupting Chemical methylparaben

The buildup of methylparaben (MP), a broad-spectrum antimicrobial preservative with endocrine-disrupting properties, in aquatic systems has become a significant concern due to its adverse health effects. Hence, introducing inexpensive and easy-to-use monitoring devices for quantifying MP is highly desirable. Thus, Zn-BTC metal-organic framework (MOF) and multi-walled carbon nanotubes (MWCNTs) functionalized with β-Cyclodextrin (β-CD) were utilized to modify the matrix of a carbon paste electrode (CPE). The morphological and electrochemical characteristics of β-CD-MWCNTs/Zn-BTC/CPE were evaluated using conventional material characterization techniques and electroanalytical methods. The sensor exhibited two linear current responses in concentration ranges of 0.01 mM to 0.3 mM and 0.3 mM to 6 mM. The limit of detection (LOD) was calculated to be 3.8 μM. The device demonstrated excellent selectivity, repeatability, reproducibility, and stability over two weeks. Evaluating its applicability in real samples achieved recoveries in the range of 96.25% to 105%, proving its reliability in environmental and industrial applications.

Determination of Mass Attenuation Coefficient of Jute Reinforced Epoxy Resin Composite as Tissue Equivalent Phantom

Abstract The mass attenuation coefficient is a fundamental parameter in radiation physics and plays a pivotal role in understanding the interaction of ionizing radiation with matter. This study aims to determine mass attenuation coefficients of newly developed tissue equivalent phantom fabricated from jute fibres reinforced with epoxy resin and activated carbon as a filler. The composites were prepared based on four different filler levels (ranging from 0wt% to 5wt%). The produced phantoms are characterized in terms of half-value layer HVL (cm) relating to linear attenuation coefficient, μ (cm−1). The linear and mass attenuation coefficients for the composites with different wt% of filler were determined at three different kV settings of the X-ray generator, covering the lower energy range of normal diagnostic practice (50 kVp, 102 kVp and 109 kVp) and by using the half-value layer (HVL) method. Aluminum filters were used to determine the HVL values and subsequently calculated the attenuation coefficients. The value of attenuation coefficients of fabricated composite materials was contrasted with theoretical value through the utilization of XCOM software at the same energy levels. The results were in good agreement for all ranges of wt% composite. These findings not only have significant practical implications for radiation-related technologies and applications but also enhance material characterization techniques. Hence, the attenuation measurements conducted in this study validate the suitability of jute-reinforced epoxy resin, filled with activated carbon as a phantom material that mimics human tissue.

Mechanistic insights into the use of flotation tail coal for enhanced water electrolysis in hydrogen production

Coal-assisted water electrolysis for hydrogen production (CAWE) is a promising method for the efficient utilization of coal resources and the sustainable generation of hydrogen. However, identifying a cost-effective and efficient carbon source remains a critical and ongoing challenge. This study proposes the use of flotation tail coal as a novel and efficient carbon source for water electrolysis. Through a combination of electrochemical experiments, thermodynamic analysis, and comprehensive material characterization techniques, this research explores the effectiveness of tail coal-assisted water electrolysis for hydrogen production (TCAWE) in enhancing hydrogen production efficiency. It is found that the catalytic effect of minerals, particularly iron and manganese ions, is instrumental in significantly reducing energy consumption and enhancing the anodic oxidation reactions in the CAWE process. Flotation tail coal, with its high content of these catalytic minerals and favorable hydrophilic surface properties, not only lowers the electrolysis voltage but also increases the hydrogen yield compared to traditional coal sources. This research innovatively demonstrates that utilizing flotation tail coal in water electrolysis offers a dual benefit: it provides a cost-effective, abundant carbon source while promoting a more efficient and sustainable hydrogen production process. Additionally, this approach is expected to facilitate the resource utilization of waste flotation tail coal.

Development and characterization of PLA food packaging composite

AbstractThis study focuses on the development of bioactive packaging materials by incorporating grape pomace and copper particles into polylactic acid (PLA) composites. The goal is to increase the shelf life of packaged foods while benefiting the health of consumers through the use of these active materials. 6 recipes of composite materials based on polylactic acid and Proviplast 2624 plasticizer were obtained. The additives added were: grape pomace, added at 0.5%, 1% and 1.5%, and copper particles, formed using PEG 600 + CuSO₄, added at 2%, 5% and 8%. Material characterization techniques: FTIR Spectroscopy, used to study the chemical structure. Differential scanning calorimetry (DSC): examined thermal transitions such as glass transition and melting temperatures. Thermogravimetric analysis (TGA) and differential thermogravimetry (DTG): evaluated thermal stability and degradation temperatures. Scanning electron microscopy (SEM) and atomic force microscopy (AFM): analyzed the surface morphology and structure. Mechanical tests: evaluated tensile strength, elongation at break and flexibility.Thermal property analyzes revealed that the additives acted as plasticizers, reducing the intermolecular forces between PLA chains, which decreased the glass transition temperature (Tg), cold crystallization temperature (Tcc) and melting temperature (Tm). The addition of grape pomace and copper particles decreased the degradation temperature of PLA composites, indicating a slight reduction in thermal stability. The transformation temperatures changed and the nature of the thermal transitions (exothermic or endothermic) varied with additive concentrations. Mechanical properties indicated a reduction in tensile strength with increasing additive concentration. Elongation at break and longitudinal modulus of elasticity increased significantly, especially with grape pomace, improving the flexibility of PLA. These changes indicate that the material can absorb more energy before breaking, making it more ductile and more suitable for flexible packaging applications. Increased flexibility and improved thermal resistance ensure that these materials can withstand the demands of packaging, handling and shipping. The combination of improved flexibility, thermal resistance and moderate tensile strength makes these PLA-based composites incorporated with grape pomace or copper particles, enhance the aspect of sustainability by recycling agricultural waste, making the material both ecological and functional, making it a viable option for active food packaging.

Electrochemistry and Cycling Dependent Structural Analysis of High and Low Mn Based Disordered Rocksalt Cathodes for Lithium-Ion Batteries

Cobalt-free cation-disordered rocksalt (DRX) materials have recently emerged as a class of next-generation high-capacity cathodes for lithium-ion batteries which can incorporate earth abundant, low-cost elements such as Mn and Ti. One of the reasons for their enhanced performance is due to the presence of percolating lithium rich clusters which enable facile lithium transport. Structural phenomena such as cation short-range ordering and phase transformations in DRX materials at small length scales are known to dramatically impact local Li clusters and hence the Li diffusion channels, Li transport, and hence electrochemical properties of DRX cathodes. Recently, Mn-rich DRX materials (Mn/Ti ratio >1) have shown to phase transform upon extended cycling, resulting in improved capacity and rate performance in these materials. Therefore, it is crucial to understand the nature of the DRX structure as a function of cycling to maximize the performance in DRX materials. Interestingly, these phase changes are not observed in DRX with a low Mn content (Mn/Ti ratio <1). Keeping this in mind, the goal of this research is to understand the structural changes during electrochemical cycling and investigate the differences in electrochemical properties (Li ion transport, rate capability, cycling) in high and low Mn DRX cathodes. In addition to the electrochemical characterization, a suite of material characterization techniques such as X-ray diffraction, X-ray absorption Spectroscopy, and pair distribution function analysis, are used to perform in depth cycling dependent structural analysis and compared between the high Mn and low Mn DRX compositions. Overall, this study and poster presentation will discuss key scientific insights related to the cycling induced phase transformation and electrochemical performance of Mn-Ti based DRX cathodes. Based on these results, further investigations into synthetic manipulation of the DRX structure can be performed to utilize the full potential of the newly formed phase upon cycling.

Solving Ambiguity in EBSD Indexing of Long-Period Stacking Ordered (LPSO) Phase in Mg with Template Matching Approach

Magnesium (Mg) alloys with long-period stacking ordered (LPSO) phases are receiving increasing interest because of their excellent mechanical performance. The close similarity in atomic stacking sequences between different LPSO polytypes and Mg lattice often leads to ambiguous indexing in electron backscatter diffraction (EBSD), a commonly used material characterization technique. Instead of the Hough transformation approach used in commercial software, an alternative indexing approach, which can catch subtle differences by matching experimental patterns with simulated ones, is explored in this study. Our results, showing ~94% of mapping data being correctly indexed as the target phase, 14H LPSO, demonstrate the capability of not only resolving the LPSO phases but also distinguishing different LPSO polytypes. This approach offers a valuable, if not unique, solution for the microscale characterization of LPSO phases, enabling precise microstructure tuning to further promote the mechanical properties of Mg alloys.

Fatigue Failure of Alloy Grade P22 Hot Reheat Auxiliary Steam Pipe

A leak was discovered in the hot reheat auxiliary pipe. The pipe was found to have a bulging condition and a crack at the base metal area. A circumferential crack was discovered near a repair weld spot on the external surface. The failure was investigated using material characterization techniques, including in-situ replication, glow discharge spectroscopy (GDS), microhardness analysis, optical microscopy, and energy dispersive X-ray spectroscopy (EDX). Based on microstructure analysis, numerous cracks were observed to have initiated at the internal surfaces of the pipe. Most of the cracks were found on the parent metal. The cluster of cracks concentrates on the plane of 0⁰ - 180⁰. Microstructure analysis shows that the cracks are multiple, parallel, mainly transgranular, oxide-filled with branching crack tips. It is thought that the cracking is associated with fatigue and, most likely, high cyclic stress is the key contributory factor. The steam oxide cracked gradually as a result of the cyclic stress. As more metal surface was exposed, new oxide formed, causing cracks to propagate into the metal as this process was repeated due to cyclic loading.

Metal-organic-framework and walnut shell biochar composites for lead and hexavalent chromium removal from aqueous environments

Extensive research in recent years has explored the realm of porous carbon composites for various applications, including electrochemistry, structural materials, environmental remediation, and more. In particular, the fabrication of porous carbon composites using a metal-organic framework (MOF) and biochar (BC) for aqueous remediation is a fairly new avenue of research. In this study, a MOF-BC composite was synthesized with unmodified and chemically modified BCs using solvothermal synthesis. The composites were used as adsorbents to remediate heavy metals, such as lead (II) and chromium (VI), from aqueous environments. It was verified that the MOF was homogeneously deposited onto the BC's surface using various material characterization techniques. Lead and chromium adsorption studies revealed a high adsorption capacity with greater than 99% removal for lead and ∼65% for chromium, respectively. Impressively, for lead, the highest observed experimental adsorption capacity of the MOF-chemically modified BC composite was 535 mg/g, compared to 240 mg/g for pristine BC. Meanwhile, the adsorption capacity of the same MOF-BC composite for chromium ions was low at 18 mg/g, compared to 80 mg/g for the chemically modified BC. The MOF-BC had a rapid adsorption rate, achieving equilibrium at only 150 min of reaction time for lead ions. MOF-BCs have higher adsorption for cationic lead through physisorption and ion-exchange mechanisms, whereas, for anionic chromium, removal is dominated only by physisorption mechanisms. The outcomes and methodological developments attained in this study offer a novel and compelling approach for synthesizing MOF-BC composites for aqueous remediation applications.

Neutron phase filtering for separating phase- and attenuation signal in aluminium and anodic aluminium oxide

Neutron imaging has gained significant importance as a material characterisation technique and is particularly useful to visualise hydrogenous materials in objects opaque to other radiations. Fields of application include investigations of hydrogen in metals as well as metal corrosion, thanks to the fact that neutrons can penetrate metals better than e.g. X-rays and are highly sensitive to hydrogen. However, at interfaces refraction effects sometimes obscure the attenuation image, which is used for hydrogen quantification. Refraction, a differential phase effect, diverts the neutron beam away from the interface in the image leading to intensity gain and intensity loss regions, which are superimposed to the attenuation image, thus obscuring the interface region and hindering quantitative analyses of e.g. hydrogen content in the vicinity of the interface. For corresponding effects in X-ray imaging, a phase filter approach was developed and is generally based on transport-of-intensity considerations. Here, we compare such an approach, that has been adapted to neutrons, with another simulation-based assessment using the ray-tracing software McStas. The latter appears superior and promising for future extensions which enable fitting forward models via simulations in order to separate phase and attenuation effects and thus pave the way for overcoming quantitative limitations at refracting interfaces.

Transition metal carbo chalcogenides: A novel family of 2D solid lubricants

Two-dimensional (2D) layered materials such as transition metal dichalcogenides (e.g., MoS2, WS2) and MXenes (e.g., Ti3C2Tx), as well as hybrids of these materials are the focus of current research in solid lubrication due to their outstanding performance. Transition metal carbo-chalcogenides (TMCCs), consisting of an MXene core and a TMD-like surface, represent an inherent combination of TMDs and MXenes without the need to construct hybrids out of the individual layers. Due to their layered structure and surface chemistry, favorable tribological properties can be expected from these novel materials. Here, multilayer Ta2S2C and Nb2S2C TMCCs are deposited solely as a powder onto a steel substrate and their tribological properties under linear sliding against different counterbodies, i.e., Al2O3, SiC, 100Cr6, and polytetrafluoroethylene (PTFE) are discussed. Advanced materials characterization techniques are used to detect the presence of TMCCs inside the wear tracks and to reveal their 2D structure within the tribofilm. Finally, density functional theory (DFT) simulations are used to unravel the easy shearability of TMCCs at the nanoscale. The results demonstrate the great potential of this new 2D material family, which also offers many possibilities for defined tuning of the solid-solid interface.

Microstructure evolution and deformation mechanisms of service-exposed P91 steel via interrupted uniaxial creep tests at 660 °C

Creep degradation behaviour of service-exposed P91 steel is evaluated during interrupted creep tests at 660 °C and 80 MPa using a number of material characterization techniques including transmission electron microscopy (TEM), scanning electron microscopy (SEM), electron backscattered diffraction (EBSD), energy dispersive spectroscopy (EDS) and optical microscopy (OM) to identify the microstructural evolution and the associated deformation mechanisms. Microhardness has also been measured in order to evaluate the softening mechanism. Under the creep conditions examined, microstructural degradation is found to be governed by the disappearance of the lath sub-structure, lath widening and recrystallization, as well as dislocation density reduction, coarsening of M23C6 and creep cavitation while MX and Laves phases are stable. Hardness evolution, extrapolated from hardness data obtained from uniaxial creep tests, is used to characterize the softening of the material. On this basis, hardness decrease is justified in term of the aforementioned microstructural changes. Implications of the findings for specific in-service life management in thermal plant piping systems are addressed.

Sustainability-oriented construction materials for traditional residential buildings: From material characteristics to environmental suitability

The increasing replacement of traditional construction materials with modern alternatives often overlooks their superior environmental adaptability and sustainability, resulting in missed opportunities for energy efficiency and carbon emission reductions. This study aimed to address this issue by scientifically evaluating the material properties of volcanic rock from Hainan Island, China, to assess its potential for sustainable building practices in tropical climates. A series of material characterization techniques were employed to analyze the composition and structure of the volcanic rock, including optical profilometry (OP), polarized light microscopy (PLM), X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscopy (SEM) with energy-dispersive spectroscopy (EDS), transient plane source technique (TPS), and mercury intrusion porosimetry (MIP). Our findings identified the rock as vesicular cryptocrystalline basalt, with its unique pore structure and mineral composition jointly contributing to a low thermal conductivity of 0.22 ± 0.04 W/(m·K). The pore structure was characterized by closed spherical cavities, needle-like lava fillings, nanoporous surfaces, complex pore-throat networks, and an extensive pore size distribution. These features significantly reduced gas convection and enhanced thermal resistance. Additionally, the rock composition, dominated by the amorphous volcanic glass and scattered hollow skeletal crystalline plagioclase, further diminished heat transfer. These characteristics indicated that Hainan volcanic rock possessed excellent thermal insulation properties, making it highly suitable for energy-efficient construction in hot climates. This study highlighted the potential for traditional materials like volcanic rock to contribute to sustainable building practices and the preservation of cultural heritage.

Advanced Electrochemical Detection of 2,4-dichlorophenol in Water with Molecularly Imprinted Chitosan Stabilized Gold Nanoparticles

2,4-Dichlorophenol (2,4-DCP) is a hazardous chemical that can be passed down to offspring. Because 2,4-DCP degrades slowly and can be passed down to future generations, it’s a pesticide that needs to be continuously monitored and managed. With the use of chitosan-stabilized AuNPs on a glassy carbon electrode and the molecular imprinting technique, an effective electrochemical sensor has been built for the selective determination of 2,4-DCP in different aqueous samples. The analyte’s electroactive surface area and number of interaction sites are both increased by the AuNPs. The formulated AuNPs were characterized using several material characterization techniques. Molecularly imprinted nanomaterials provided the selectivity against other interfering chlorophenols. With a detection limit of 6.33 nM and a broad linear dynamic range of 21.09 to 310 nM, 2,4-DCP was found using differential pulse voltammetry. Without interference from structural analogs, the sensor was effectively evaluated in a variety of contaminated water samples.